This chapter explains MySQL Group Replication and how to install,
configure and monitor groups. MySQL Group Replication is a MySQL
Server plugin that enables you to create elastic, highly-available,
fault-tolerant replication topologies.

Groups can operate in a single-primary mode with automatic primary
election, where only one server accepts updates at a time.
Alternatively, for more advanced users, groups can be deployed in
multi-primary mode, where all servers can accept updates, even if
they are issued concurrently.

There is a built-in group membership service that keeps the view of
the group consistent and available for all servers at any given
point in time. Servers can leave and join the group and the view is
updated accordingly. Sometimes servers can leave the group
unexpectedly, in which case the failure detection mechanism detects
this and notifies the group that the view has changed. This is all
automatic.